Under the proposals, NHS England suggested that a practice exceeding a threshold number of out-of-area patients in any CCG of 1,000-2,000 patients would see its main contract 'automatically disaggregated'.

Responding to the consultation, Babylon warned that such list size at CCG level would 'not be sustainable to staff'.

The consultation said: 'The key decision is the choice of threshold at which to trigger the creation of a new APMS contract. Set too low, the danger would be a series of contracts serving very few patients. Set too high, the danger is that the detractions of the current model are perpetuated for too many patients. We are therefore consulting on the correct threshold, but our starting proposition is that a threshold of between 1,000 and 2,000 patients might be used.

'To avoid bureaucracy and uncertainty for GPs, CCGs and patients, the establishment of new contracts by this route would be an automatic process involving default bulk and automatic re-registration of patients with the same provider under its new contract.

'These changes would oblige the commissioner and provider to undertake this process.'

But Babylon said in its response that proposing a patient list of 1,000 at CCG level instead of ICS level will not be 'sustainable to staff'.

The response said: 'Sustainability is critical for all providers. Access to a significant population and geography is necessary for the sustainability of each clinic site, given that over 80% of Babylon GP at Hand consultations are dealt with to completion without the need for in-person primary care input. This means that per unit of clinical space, digital-first providers can serve five or more times the patient list from a given clinic than a traditional provider.

'Practically, at a list size of 1,000 in a CCG and assuming five appointments / member / year, a clinic would be used for as few as 1,000 physical appointments, or ~20 per week. This is not sustainable to staff. Hence the need to link clinics to STPs / ICSs rather than CCGs, as the larger initial and addressable population is necessary to achieve a sustainable operating model.'